Last year's league rushing leader was already cleared to play in the opener against the New York Giants on Sunday night before the ruling by U.S. District Judge Amos Mazzant.

Mazzant agreed with players' union lawyers that Elliott didn't receive a "fundamentally fair" hearing in his appeal and he granted the NFL Players' Association request for a temporary restraining order and preliminary injunction blocking the league's punishment.

Elliott was suspended by Commissioner Roger Goodell in August after the league concluded he had several physical confrontations last summer with Tiffany Thompson, a former girlfriend. Prosecutors in Ohio didn't pursue the case, citing conflicting evidence.

The 22-year-old Elliott denied Thompson's allegations in sworn testimony during an appeal hearing last week. He also attended the hearing for a restraining order earlier this week in Sherman, about 65 miles north of Dallas.

Arbitrator Harold Henderson turned down Elliott's appeal of the suspension the same day as the hearing in federal court. Henderson ruled that the NFL complied with its personal conduct policy in punishing Elliott and rejected any claims that Elliott's attorneys presented new evidence at the appeal.

Mazzant ruled that Henderson's decision not to allow Goodell and Thompson to testify helped Elliott's case in meeting the standard for an injunction to be issued.

"Their absence effectively deprived Elliott of any chance to have a fundamentally fair hearing," Mazzant wrote.

The union blasted NFL owners in its reaction to Mazzant's ruling.

"Commissioner discipline will continue to be a distraction from our game for one reason: because NFL owners have refused to collectively bargain a fair and transparent process that exists in other sports," the union said. "This 'imposed' system remains problematic for players and the game, but as the honest and honorable testimony of a few NFL employees recently revealed, it also demonstrates the continued lack of integrity within their own league office."

After Henderson's ruling, the NFL filed a lawsuit asking a federal court in New York to enforce Elliott's suspension. The Southern District of New York falls under the 2nd U.S. Circuit Court of Appeals, which last year backed Goodell's four-game suspension of New England quarterback Tom Brady in the "Deflategate" case.

The union had sued in federal court on behalf of Elliott last week before Henderson ruled, saying the appeal hearing was "fundamentally unfair" because the running back was prevented from confronting his accuser in the Ohio case.

NFLPA attorney Jeffrey Kessler reiterated most of the union's arguments before Mazzant, who pressed league attorney Daniel Nash for answers on the claim from Elliott's legal team that a co-lead investigator who questioned Thompson's credibility was left out of a key meeting with Goodell during the yearlong probe.

According to the letter Elliott received informing him of the suspension last month, the NFL believed he used "physical force" three times in a span of five days in a Columbus, Ohio, apartment last July resulting in injuries to Thompson's face, neck, shoulders, arms, hands, wrists, hips and knees.

Prosecutors in Columbus decided about a year ago not to pursue the case in the city where Elliott starred for Ohio State, but the NFL kept the investigation open. The league said its conclusions were based on photographs, text messages and other electronic evidence.

The NFL stiffened penalties in domestic cases three years after the league was sharply criticized for its handling of the domestic case involving former Baltimore running back Ray Rice.

Elliott rushed for 1,631 yards as a rookie to help the Cowboys to the best record in the NFC at 13-3. He was a full practice participant throughout training camp but played in just one preseason game, same as a year ago when Elliott missed significant time at camp because of a hamstring injury.